Improvement in screw-drivers



UNITED STATES PATENT OFFICE.

WILLIAM F. PATTERSON, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN SCREW-DRIVERS.

Specification forming part of Letters Patent No. 1 58,807, dated January 19, 1875; application filed November 2, 1874.

T 0 all whom it may concern Be it known that I, WILLIAM F. PATTER- SON, of Boston, in the county'of Sufl'olk, State of Massachusetts, have invented a certain new and useful Improvement in Screw-Drivers, of which the following is a description suflicient- 1y full, clear, and exact to enable any person skilled in the art or science to which my invention appertains to make and use the same, reference being had to the accompanying drawing, forming a part of this specification, in which Figure 1 is an isometric-a1 perspective view.

My invention relates to that class of'screwdrivers which are provided with adjustable or reversible blades; and consists of a novel construction and arrangement of the parts, as hereinafter more fully set forth and claimed, as an improvement upon the patent granted to me November 24,1874, No. 157,102.

In the drawing, A is the haft or handle; B, the main or central blade; 0, a clamp or sleeve attached to the main blade, and E F auxiliary blades. The clamp O is provided with the thumb or set screws D D upon two of its opposite sides, and is of the proper form and ca pacity to admit the blades'E F, as shown, and permit them to slide freely along the central blade when the screws D D are released. The auxiliary blades are provided with the indentations G G, for enabling the screws D D to retain them in position, and also with the gagemarks H H, to determine when the indentations and inner end of the screw are coincident or correspond in position as the auxiliary blades are advanced or withdrawn.

From the foregoing the nature and operation of my invention will be readily obvious to all conversant with such matters.

It will be obvious that either of the blades E F may be advanced for use, and reversed or withdrawn, as occasion may require 5 or that they may be removed entirely, and the central blade be used until the auxiliary blades are needed.

Having thus explained my invention, what I claim is In a screw-driver, the blade B, having the fixed clamp O projecting upon both sides thereof, and provided with the screws D D, in combination with the detachable and reversible blades E F, having the indentations G G and gage-marks H H, constructed to operate substantially as and for the purpose specified.

WILLIAM F. PATTERSON.

Witnesses:

G. A. SHAW, H. E. METCALF. 

